Answer:
Vertical Angles are Congruent
Explanation:
Angle BCA and angle DCE are congruent since they are vertical angles. Lines BE and AD cross each other to make vertical angles. You can't really know if BC equals EC for sure, as well as how Alternate Interior Angles are Congruent. I don't know how else I can explain this, but I hoped it helped you understand why it is A = Vertical Angles are Congruent.